This invention relates to improvements in gas absorption techniques, and more particularly concerns a reflux concentrator for scrubbing contaminated gases with a solvent liquid. This invention is especially useful in measuring indirectly the trace levels of discrete constituents present in studied sample gases.
Many constituents exist in the atmosphere as trace gases. Despite the minute concentrations of these atmospheric constituents, trace gas constituents can greatly affect the quality of both the atmosphere and the environment as a whole. Such an impact on atmospheric and environmental quality compels the monitoring of these trace constituents. Since directly measuring the minute concentrations of these trace constituents is often impractical if not impossible, preconcentration to measurable levels is usually necessary when using conventional equipment. A commonly used method of preconcentration is gas absorption, whereby trace constituents from a large amount of sample gas are removed and concentrated in a fixed quantity of scrubbing liquid. The concentrated levels of trace constituents in the liquid are readily measured thus providing a basis for calculating the constituent content level of the prescrubbed sample gas. Most of the devices employed for gas absorption fall into the broad categories of bubblers or sprayers. These devices are typically too cumbersome and slow for field use as they require both large quantities of scrubbing liquid and long sampling periods to reach measurable concentration levels. If preconcentration could be achieved more quickly and with less scrubbing liquid, field measurements would be greatly facilitated.
Accordingly, it is an object of this invention to provide a gas absorption device facilitating measurements of trace gases present in sample gases.
Another object of this invention is to provide a gas absorption device permitting field operation by semi-skilled operators.
Another object of this invention is to provide a gas absorption device requiring less scrubbing liquid for a given quantity of sample gas than required by conventional scrubbers achieving the same extraction efficiency.
Another object of this invention is to provide a gas absorption device requiring less time to reach a measurable concentration level of trace constituents in its scrubbing liquid for a given quantity of gas than the time required by conventional scrubbers achieving the same extraction efficiency.
Yet another object of this invention is to provide a gas absorption device capable of scrubbing higher gas flow rates (8 1/min and above) than are processable with conventional scrubbers of similar size achieving the same extraction efficiency.
A further object of the invention is to provide a gas absorption device with sufficiently low back pressure at a 8 1/min sample inlet rate to permit direct sampling from an aircraft without the need for pumps.